Bioinspired soft molds enabling high-fidelity microstructure replication via stress relief

Inspired by the hierarchical micro/nanostructures of rose petals, we report a bioinspired strategy to fabricate flexible soft molds featuring stress-adaptive surface architectures. Conventional molding techniques often face challenges in thermal stress management, typically limited by the intrinsic thermal or mechanical properties of the material. Here, we introduce gradient energy-dissipating structures into the mold surface, enabling effective stress relief through spatially distributed dissipation pathways. This approach allows high-fidelity replication of functional microstructures using polydimethylsiloxane(PDMS)-based soft molds. Compared to conventional molds, the bioinspired design reduces peak stress by 2-3 times and decreases structural deformation by up to 54.58%. Mechanistic analysis reveals that lowering the PDMS mixing ratio and minimizing melt flow paths significantly improves replication fidelity, while microstructure aspect ratio (AR=0.06 to 2.25) exerts little influence, with fidelity consistently exceeding 98%. To explore scalability, a high-aspect-ratio microneedle array (AR=5) was successfully replicated through optimized temperature and pressure parameters. Functional validation-such as microdroplet generation, in situ bacterial culture, and Gram staining-confirms the applicability of the fabricated chips in single-cell analysis and rapid pathogen detection. This bioinspired molding strategy integrates structural and functional design, offering a versatile platform for stress-relieved, high-precision replication and bioanalytical applications. • A bioinspired flexible mold with gradient energy-dissipating structures was developed to relieve thermal stress. • The design reduces peak stress by 2–3× and deformation by up to 54.58% during microstructure replication. • High-fidelity molding (>98%) was achieved across microstructures with aspect ratios ranging from 0.06 to 5. • Replicated chips support single-cell bioassays, including droplet generation, bacterial culture, and Gram staining.